1  –  CASCADE

    Specifies that you want SQL to delete all other view definitions
    that refer to the named view and then delete that view
    definition. This is known as a cascading delete. If you delete
    a view referenced by a stored routine or trigger with a routine
    or language-semantic dependency, SQL also marks the affected
    routines and triggers as invalid.

2  –  IF_EXISTS

    Prevents SQL command language from displaying error messages if
    the referenced object does not exist in the database.

3  –  RESTRICT

    Specifies that you want SQL to delete only the named view
    definition. If there are other views, triggers, or routines that
    refer to the named view, the deletion fails. RESTRICT is the
    default.

4  –  view-name

    Specifies the name of the view definition you want to delete.